Stitch control for sewing machines



J. A. FLANAGAN. STITCH CONTROL FOR SEWING MACHINES. APPLICATION FILED JULY 8, 1920.

1,404,357. Patented Jan. 24, 1922,,

4 $HEETSSHEET l.

ATTORNEY 1. A. FLANAGAN. STITCH CONTROL FOR SEWING MACHINES.

APPLICATION FILED JULY 8,1920- 7 Patented Jan. 24, 1922.

4 SHILE IS SHEET 2 ATTom/EK J. A. FLANAGAN.

STITCH CONTROL FOR SEWING MACHINES.

APPLICATION HLED JULY 8,1920.

1 ,404, 357 Patented Jan.'24, 1922.

4 $HhETSSHEET 3.

ATTORNEY J. A. FLANAGAN.

STITCH CONTROL FOR SEWING MACHINES.

APPILICATION FILED JULY 8,1920.

l ,104,357. Patented Jan. 24, 1922.

4 $HLETS-SHEET 4.

fVVE/VTOR, 4 W 4 W4- 4 Lin ATTORNEY JAMES ALEXANDER FIl- -NAGAN, OF TORONTO, ONTARIO, CANADA.

STITCH CONTROL FOR SEWING MACHINES.

' Specification of Letters Patent.

Patented Jan. 24, 1922.

Application filed July 8, 1920. Serial No. 394,794.

To all whom it may concern:

Be it known that 1, JAMES ALEXANDER FLANAGAN, residing at the citygof Toronto, in the county of York and Province of Ontario, Dominion of Canada, have invented certain new and useful Improvements in Stitch Controls for Sewing Machines; and I hereby declare that the following is a full, clear, and exact description of the same.

This invention relates to a sewing machine provided with adjustable means, combined with the stitch control mechanism, for deter.-

' mining the length of stitch simultaneously for the forward and reverse feeds, and it consists essentially of a lever for adjusting the stitch control mechanism, a pair of adjustable stops to limit the movement of the lever in opposite directions, and a right and left threaded screw for adi'usting the stops The invention further re ates to means for moving the control lever between the stops to change the direction of the feed, this means comprising a rock shaft havinga pair of cranks, one of which is. connected by a rod with, the control lever, and the other of 'which constitutes the means by which the rock shaft is actuated, as hereinafter set forth and particularly pointed out in the claims. I

In the accompanying drawings; Fig. l, is a longitudinal sectional elevation of a sewing machine with some of the parts in section and others in elevation,

Fig. 2, is a cross-section on the 11ne 22,

F ig. 3, is afront elevation of the same parts of the machine as shown in Fig. 2,

Fig. 4, is a sectional elevation of the feed control mechanism showing the different adjustments, and

F i .5, is 'a detail view showing the gauge for t e adjustments shown in Fig. 4.

The bed-plate 1, overhanging arm 2,

needle-shaft 3, looper-shaft 4 and their ad-' juncts may be of any usual or approved construetion and arrangement, and so also may be other parts shown in'the drawing and not otherwise specifically described herein.

5 is a rock-shaft, made hollow and surrounding the looper-shaft 4, and having at its front end a crank arm 6 to engage the feeddog. This shaft 5 herein referred to as the feed shaft, has at its rear end a crank arm 7 set quartering or otherwise thereon with relation to the crank arm 6. The looper shaft 4 has a grooved crank arm 8 at its rear end slidingly engaged by a roller 9 on the end of a connecting rod 10 which connects with a crank 11 on the needle shaft 3 and is I gated slot 12, and within this slot is a rocking member or fulcrum 13 loosely mounted upon a fixed pivot pin 14, the inner end of said pin being screwed or otherwise fixed in a support 15 pr0jecting within the hollowv upright of the overhanging arm and preferably cast integral with one side of it. Durmg the rotation of the needle shaft the crank 11 and fulcrum 13 impart an oscillating reciprocating movement to the connecting rod 10, and cause the roller 9 to travel to and from the axis of the looper shaft in its sl1d1ng connection with the crank arm 8. When the looper is picking up the loop the roller 9 is at or near the outer end of the crank arm 8, and is then revolving thelooper shaft at a relatively slow speed. When the loop has been icked up the roller 9 moves inward along tlie crank arm 8 towardsthe axis of the looper shaft, and gradually increases the speed of revolution until the maximum speed of rotation is attained and then moves outwardly along the arm to again decrease the speed of rotation to enable the looper to pick up the next loop; 16 is an arcuate' lever or link pivoted centrally or thereabout on a screw or other pivot 17 fixed to the upright support 15. This lever or link has an undercut or equivalent arcuate groove 18 in its face to receive a roller 19 on the upper end of a connecting rod- 20 which is pivoted at 20 to the crank arm 7 and this roller 19 enters and works in the groove 18 of the lever or link 16. The are of the groove 18 is concentric with the pivot 20 for the free movement of the roller 19 when shifted therein, as hereinafter described.

The lever or link 16 has applied to one of its ends a pitman 21 whlch extends to and engages with an eccentric or crank 22 on longitudinal slot 23 which receives a pin 24 on the end of one arm 25 of a bell-crank control lever 25, which is pivoted on a p1n 26 supported at opposite ends in the upright part of the arm 2 and the support 15. The other arm 25 of the bell-crank lever is extended through a vertically elongated slot 27 in the arm 2', and is provided with a clamping nut 30-to hold it in its adjusted position. As the bell-crank lever is rocked it serves to selectively shift the roller end of the connecting rod to one side or the other of the pivot or axis of the arcuate lever or link 16, and thereby change the direction of'movement of the feed dog and consequently that of the stitching, and it also serves to position the roller at points between the axis of the arcuate lever or link and one or the other of its ends so as to vary the throw of the connecting rod 20, and consequently the length of the arc of movement of the crank arm 7 and the length of movement of the feed-dog and length of stitch. The full and dotted lines Fig. 4, indicate possible variations of thesort. referredto,

and the curvature of the arcuate groove 18 being concentric-with the pivot 20 of the connecting rod 20 permitsof the connecting rod being shifted to reverse or change the length 0 stitch, while the machine is running.

To determine the limit of movement of the bell-crank lever 25, two adjustable stops 31 and 32 are arranged within the arm 2, one above and the other belowthe lever arm 25'. These stops are arranged in alignment at one side of said lever arm, and each has a vertical screw threaded bore 33.

The arm 2, at the sides of the slot 27 is curved on a radius preferably from the center of the pin 26, as shown at 2, and

above the curved part 2 isa ledge 2*, overhanging the stops. Formed through the ledge 2 is a bore 35 in line with the bores of the stops 31 and 32. Passing through the bore 35 and through the bores of the stops 31 and 32, is a screw 36, the lower-part of .which is left threaded, and the upper part of which is right threaded, with a shoulder or unthreaded part 39 interjacent the threads to arrest the movement of the stops at what may be termed the zero position of the control lever 25.

On the outer end of the screw 36 is a knurl'ed head 40, by which it is rotated to change the position of the stops 31 and 32. The arm 25 oscillates between the stops 31 and 32 during the change of direction of shaft 44 is provided with as econd crank 45,

which constitutes the means by .which the rock shaft is actuated to move the arm 25*,

of the control lever, to the limit determined by the stops 31 and 32. The crank 45 is shown to be provided with a rod 46, having a knee band 46, by which it may be move by the knee of the machine operator, when the machine is driven by power to enable the machine operator to change the direction of the feed while the machine is runnin without releasing the hands from the wor The curved art of the arm 2 may have a graduated dia reading in both directions from a zero position as shown at 48 and the bell crank arm 25 may be provided with a pointer 48*, the ointer and the graduations of the dial indicatin the positlon of the control lever for the. esiredlen h of feed and consequently the length of t e stitch to be made by the machine. These graduations may be any sub-division of an inch, and when'the stops are set the length'of the stitch during the feed in one direction will be exactly the same as the length of feed in the opposite direction. B sett ng the stops for any desired length of stitch, the machine will form a stitch of the machine will form a stitch of the same len h in the opposite direction, the change of irection being .possible when the'machine is running. 1 v

The curvature of the arcuate lever orlink 16 and its groove 18 being concentric with the pivot'20 of the connecting rod permits of the roller 19 being shifted r to reverse positions and vice versa to the limit of motion in either direction and any oint intermediatethe pivot 17 and these llmits without disturbing the vertical reciprocation of the feed do and for this reason the curvature of, t e arcuate lever or om forward link has been described from the pivot center 20 and rockson the pivot 17 during the shiftin of the roller 19 to vary the length of stitc and the direction of the feed.

.' Variations in details of construction and arrangement of parts are contemplated as being within the principle and scope of the invention as hereinafter claimed.

Having thus fully described my inven tion, what I claim as new and desire to secure by Letters Patent 1s: 7

1. In a sewing machine. a driving shaft, a

driven feed shaft, and a lever mechanism interpos'ed between and connected with these shafts, comprising a connecting feed shaft and a rockable lever with which the connecting rod has adjustable connection, the combination of a control lever for rod for the shafts, comprising a connecting rod for the feed shaft and a rockable arcuate lever with which the connecting rod has adjustable connection, the'combination of a control lever for the adjustment of the connecting rod, and adjustable means limiting the movement of the control lever and determining the length of stitch equally for the forward and reverse feeds. a J

3. In a sewin machine, a driving shaft; a driven feed sha and a lever mechanism interposed between and connected with these shafts, comprising a connecting rod for the feed shaft, and a rockable lever-with which the connecting rod has adjustable connection, the combination of a control lever for adjustable stops arranged on opposite sides of the other arm limitlng 'the movement of the control lever and determining the length of stitch equally-for the forward and reverse feeds, and a setting screw simultaneously positioning the stops.

7, A sewing machine comprising adjustable means combined with the stitch control mechanism for determining the length of stitch simultaneously for the forward and reverse feeds, consisting of a lever for adjusting the stitch control mechanism, a pair of adjustable stops to limit the movement of said lever in opposite. directions, and means for moving the lever between said stopsto change the direction of the feed, consisting of a rock shaft having a air of cranks, one of which actuates the roc shaft and the other of which :is connected with the stitch control lever.

8. In a sewing machine the combination of a driving shaft and a driven feed shaft, with a compound lever mechanism interposed between and connected with these the adjustment of the connecting rod, and shafts, said lever mechanism comprising a adjustable stops arranged on opposite sides of the control lever limiting its movement and determinin the length of stitch equally for the forwar and reverse feeds.

4. In a sewing machine, a driving shaft, a

driven feed shaft, and a, lever mechanism interposed between and connected with these shafts, comprising a connecting rod for the feed shaft and a rockable lever with which the connecting rod has adjustable connection, the combination of a control lever for the adjustment of the connecting rod, ad justable stops limiting the movement of the control lever and determining the length of stitch equally for the forward and reverse feeds, and a setting screw simultaneously positioning the stops. I

5. In a sewing machine, a drivin shaft, a driven feed shaft, and a lever mec anism interposed between and connected with these shafts, comprising a connecting rod for the feed shaft and .a rockable lever with which the connecting rod has adjustable connection, the combination of a control lever for the adjustment of the connecting rod, and adjustable means limiting the movement of the control lever and determining the length of stitch equally for the forward and reverse feeds, a stationary dial, and a pointer for the control lever, indicating the length.

of stitch. 1

6. In a sewing machine, a driving shaft, a driven feed shaft, and-a lever mechanism interposed between and connected with these shafts, comprising a rockable lever, and a connecting rod for the feed shaft having an adjustable connection with the rockable lever, the combination of a bell crank control lever one arm of which has a moving connection with the connecting rod, a pair of connecting rod for the feed shaft, an arm-- ate lever concentric with the connection of said rod with the feed shaft, and a shiftable connection between the connecting rod and the arcuate lever.

9." In a sewing machine the combination of a driving shaft and a driven feed shaft, with a compound lever mechanism interposed between and connected with these shafts, said lever mechanism comprising a connecting feed shaft, anarcuate lever concentric with said pivotal connection, a fixed pivot on which the arcuate lever rocks and a shiftable connection between the connecting rod and the arcuate lever.

11. In a sewing machine the combination of a driving shaft and a driven feed shaft, with a compound lever mechanism interposed between and connected with these shafts, said lever mechanism comprising a connecting rod pivotally connected with the feed shaft, an arcuate lever concentric with said pivotal connection,a fixed ivot on which the arcuate lever rocks, a shi table connection between the connecting rod and the arcuate lever, and a connection between I the arcuate lever and the driving shaft.

12. In a sewing machine the combination of a driving shaft and a driven feed shaft, with a compound lever mechanism interposed between and connected with these shafts, said lever mechanism comprising a connecting rod having a pivotal connection with the feed shaft, an arcuate lever rock-- able on a fixed pivot and concentric withsaid pivotal connection, a shiftable connection between the connecting rod and the arcuate lever, and a connection between thearcuate' lever and thedriving shaft.

13. In a sewing machine the combination of a driving shaft and a driven feed shaft with a compound lever mechanism interposed between and connected with these shafts, said lever mechanism comprising a connecting rod having a pivotal connection with the feed shaft, an arcuate lever concentric with said 'pivotal connection, and a roller for the connectin rod having a shiftable connection with t e arcuate lever.

14. In a seWin machine the combination of a driving sha t and a driven feed shaft with a compound lever mechanism inter 

